Power converter implementations, programmable gain, and programmable compensation

ABSTRACT

A power supply includes a voltage converter to produce an output voltage to power a load. The power supply further includes a reference voltage generator and a controller. The reference voltage generator is operative to generate a floor reference voltage that varies as a function of the output voltage depending on a setting of one or more adjustable (programable) resistor-capacitor paths in the floor reference voltage generator. The controller produces control signals to control the voltage converter as a function of the floor reference voltage and the output voltage.

BACKGROUND

Conventional power supplies may include one or more DC-to-DC convertersto produce a respective output voltage to power a load. One type ofDC-to-DC converter is a single-stage power converter system. As its namesuggests, in the single-stage power converter system, each phaseincludes a single power converter to convert an input voltage such as 12VDC (Volts Direct Current) into a respective target output voltage suchas 1 volt DC to power a load.

If desired, a conventional power converter can be configured to operatein a so-called diode emulation mode in which high side switch circuitryis occasionally pulse to an ON state to maintain regulation of an outputvoltage while corresponding low side switch circuitry is always disable(OFF). Additionally, a conventional power converter can be configured tooperate in a so-called continuous conduction mode in which high sideswitch circuitry and low side switch circuitry are activated atdifferent times.

Thus, in general, to maintain an output voltage within a desired range,the buck converter compares the magnitude of a generated output voltageto control respective switch circuitry (such as a control switch andsynchronous switch).

BRIEF DESCRIPTION

Embodiments herein include novel ways of improving an efficiency andaccuracy of generating an output voltage.

More specifically, a power supply (such as an apparatus, device, system,etc.) includes a voltage converter to produce an output voltage to powera load. The power supply further includes a floor reference voltagegenerator and a controller. During operation, the floor referencevoltage generator generates a floor reference voltage that varies as afunction of the output voltage as well as a setting of one or moreadjustable resistor-capacitor paths disposed in the floor referencevoltage generator. The controller produces control signals (a.k.a.,control output) to control the voltage converter as a function of thefloor reference voltage and the output voltage.

In accordance with further example embodiments, the power supply asdescribed herein includes a ramp voltage generator. The referencevoltage generator produces a ramp voltage. In one embodiment, the rampvoltage is offset by a magnitude of the floor reference voltage. Thecontroller produces the control output (one or more control signals)based on a comparison of the output voltage and the offset ramp voltage.

In yet further example embodiments, the floor reference voltagegenerator includes a floor reference voltage amplifier operative toproduce the floor reference voltage. An adjustable resistor-capacitorpath is disposed in a feedback path of the floor reference voltageamplifier. In one embodiment, the adjustable resistor-capacitor path inthe feedback path of the floor reference voltage generator controls again such as an AC (Alternating Current) gain of the floor referencevoltage amplifier. Thus, variations in the adjustable resistor-capacitorpath results in variations to the corresponding gain provided by theadjustable resistor-capacitor path.

In still further example embodiments, the floor reference voltagegenerator includes a floor reference voltage amplifier that produces thefloor reference voltage. In such an instance, the adjustableresistor-capacitor path is disposed in a circuit path between an outputof a sense amplifier stage and an input of the floor reference voltageamplifier. In one embodiment, the sense amplifier stage compares theoutput voltage to a reference voltage. Based on the comparison, thesense amplifier generates an error voltage signal (which may be offsetwith respect to ground). The sense amplifier inputs the respectivegenerated error voltage signal into the circuit path (adjustableresistor-capacitor path) to the floor reference voltage amplifier. Inone embodiment, the adjustable resistor-capacitor path provides a zeroto the reference voltage generator circuit for stability of the powersupply. A setting of the adjustable resistor-capacitor path (such as RCvalue) provides a setting of a zero associated with the floor referencevoltage generator.

In accordance with further embodiments, the adjustableresistor-capacitor path provides phase margin compensation to the floorreference voltage generator. In other words, a programmed setting of theadjustable resistor-capacitor path controls a phase response of thefloor reference voltage generator.

Note that the one or more adjustable resistor-capacitor paths in thefloor reference voltage generator can be implemented in any suitablemanner.

For example, in one embodiment, the adjustable resistor-capacitor path(such as a first adjustable resistor-capacitor path of multipleadjustable resistor-capacitor paths in the power supply) includes acapacitor ladder (multiple capacitors). The power supply furtherincludes a first RC (resistor-capacitor) path controller that, while theresistor is set to fixed resistor value, controls a capacitance of thecapacitor ladder in the adjustable resistor-capacitor path to a desiredcapacitance setting. In such an instance, the first RC path controllerselects how many of the one or more capacitors of the capacitor ladderare connected in parallel or series depending on a respective controlsignal inputted to the capacitor ladder. Via changes in the number ofcapacitors of the capacitor ladder that are connected in parallel orseries, the first RC path controller controls a capacitance setting andthe overall RC setting of the first adjustable resistor-capacitor pathand thus corresponding circuit behavior (phase response and gainresponse) associated with the floor reference voltage generator.

In an example embodiment, the adjustable resistor-capacitor path (suchas a second adjustable resistor-capacitor path of multiple adjustableresistor-capacitor paths in the power supply) includes a resistor ladder(multiple resistors). The power supply further includes a second RC(resistor-capacitor) path controller that, while the capacitor iscontrolled to a fixed capacitor value, controls a resistance of theresistor ladder in the second adjustable resistor-capacitor path to adesired resistor setting. The second RC path controller selects how manyof the one or more resistors of the resistor ladder are connected inparallel or series depending on a respective control signal inputted tothe resistor ladder. Via changes in the number of resistors of theresistor ladder that are connected in series or parallel, the second RCpath controller controls a resistance setting and thus overall RCsetting of the adjustable resistor-capacitor path and correspondingcircuit attributes associated with the floor reference voltagegenerator.

In accordance with further example embodiments, the adjustableresistor-capacitor path receives a ripple voltage (such as from a senseamplifier stage) and provides a zero compensation to a floor referencevoltage amplifier in the floor reference voltage generator.

Further embodiments herein include implementing multiple (programmable)adjustable resistor-capacitor paths in the power supply to provideimproved generation of an output voltage of different operationalconditions (such as steady state conditions and transient conditions).For example, in one embodiment, the power supply as described hereinincludes a first adjustable resistor-capacitor path and a secondadjustable resistor-capacitor path. The reference voltage generatorfurther includes a floor reference voltage amplifier that produces thefloor reference voltage. The first adjustable resistor-capacitor path isa first adjustable resistor-capacitor path disposed in a feedback pathof the floor reference voltage amplifier. In a manner as previouslydiscussed, selected settings of the first adjustable resistor-capacitorpath controls an AC (Alternating Current) gain response of the floorreference voltage amplifier. Selected settings of the second adjustableresistor-capacitor path provide a setting of a zero circuit associatedwith the floor reference voltage generator.

In yet further example embodiments, the setting of each of the one ormore adjustable resistor-capacitor paths is automatically tuned by adigital state machine based on one or more of: i) a selected switchingfrequency, ii) an output current of the voltage converter, and iii) ameasured temperature.

Embodiments herein are useful over conventional techniques. For example,the implementation of programming one or more adjustableresistor-capacitor paths as described herein is a unique way toimplement compensation in the power supply circuit as described herein.

These and other more specific embodiments are disclosed in more detailbelow.

Note that techniques as discussed herein can be implemented in anysuitable environment such as amplifier circuitry, power supplies, powerconverters, multi-phase power supply applications, single phase point ofload (a.k.a., POL) power supply applications, etc.

Note further that although embodiments as discussed herein areapplicable to multi-phase power supply circuits such as thoseimplementing buck converters, DC-DC converter phases, the conceptsdisclosed herein may be advantageously applied to any other suitabletopologies as well as general power supply control applications.

Additionally, note that embodiments herein can include computerprocessor hardware (that executes corresponding switch instructions) tocarry out and/or support any or all of the method operations disclosedherein. In other words, one or more computerized devices or processors(computer processor hardware) can be programmed and/or configured tooperate as explained herein to carry out different embodiments of theinvention.

Yet other embodiments herein include software programs to perform thesteps and operations summarized above and disclosed in detail below. Onesuch embodiment comprises a computer program product that hasnon-transitory computer-storage media (e.g., memory, disk, flash, . . .) including computer program instructions and/or logic encoded thereonthat, when performed in a computerized device having a processor andcorresponding memory, programs the processor to perform any of theoperations disclosed herein. Such arrangements are typically provided assoftware instructions, code, and/or other data (e.g., data structures)arranged or encoded on a computer readable storage medium ornon-transitory computer readable media such as an optical medium (e.g.,CD-ROM), floppy or hard disk or other a medium such as firmware ormicrocode in one or more ROM or RAM or PROM chips, an ApplicationSpecific Integrated Circuit (ASIC), circuit logic, etc. The software orfirmware or other such configurations can be installed onto a respectivecontroller circuit to cause the controller circuit (such as logic) toperform the techniques explained herein.

Accordingly, one embodiment of the present disclosure is directed to acomputer program product that includes a computer readable medium havinginstructions stored thereon for supporting conversion of a DC inputvoltage into a DC output voltage. For example, in one embodiment, theinstructions, when carried out by computer processor hardware (one ormore computer devices, control logic, digital circuitry, etc.), causethe computer processor hardware to: produce an output voltage to power aload; generate a floor reference voltage that varies as a function ofthe output voltage and depending on a setting of an adjustableresistor-capacitor path; and produce control output to control thevoltage converter as a function of the floor reference voltage and theoutput voltage.

The ordering of the operations has been added for clarity sake. Theoperations can be performed in any suitable order.

It is to be understood that the system, method, device, apparatus,logic, etc., as discussed herein can be embodied strictly as hardware(such as analog circuitry, digital circuitry, logic, etc.), as a hybridof software and hardware, or as software alone such as within aprocessor, or within an operating system or a within a softwareapplication.

Note that although each of the different features, techniques,configurations, etc., herein may be discussed in different places ofthis disclosure, it is intended, where appropriate, that each of theconcepts can optionally be executed independently of each other or incombination with each other. Accordingly, the one or more presentinventions as described herein can be embodied and viewed in manydifferent ways.

Also, note that this preliminary discussion of embodiments hereinpurposefully does not specify every embodiment and/or incrementallynovel aspect of the present disclosure or claimed invention(s). Instead,this brief description only presents general embodiments andcorresponding points of novelty over conventional techniques. Foradditional details and/or possible perspectives (permutations) of theinvention(s), the reader is directed to the Detailed Description sectionand corresponding figures of the present disclosure as further discussedbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example diagram illustrating a power supply including oneor more adjustable resistor-capacitor paths disposed in a floorreference voltage generator according to embodiments herein.

FIG. 2 is an example diagram illustrating a power supply andimplementation of multiple adjustable resistor-capacitor paths in apower supply according to embodiments herein.

FIG. 3 is an example diagram illustrating a specific implementation ofmultiple adjustable resistor-capacitor paths in a floor referencevoltage generator according to embodiments herein.

FIG. 4 is an example diagram illustrating a transfer function (phase andgain responses) associated with the floor reference voltage generatorfor different zero settings of a respective adjustableresistor-capacitor path in a floor reference voltage generator accordingto embodiments herein.

FIG. 5 is an example diagram illustrating a transfer function (phase andgain responses) associated with a floor reference voltage generator andimplementation of an AC gain adjustment provided via control of acorresponding adjustable resistor-capacitor path according toembodiments herein according to embodiments herein.

FIG. 6 is an example diagram illustrating implementation of a voltageconverter according to embodiments herein.

FIG. 7 is an example diagram illustrating different operation of a powersupply in a fixed floor reference voltage mode and variable floorreference voltage mode according to embodiments herein.

FIG. 8 is an example diagram illustrating computer processor hardwareand related software instructions or logic circuit operative to executemethods according to embodiments herein.

FIG. 9 is an example diagram illustrating a method according toembodiments herein.

FIG. 10 is an example diagram illustrating fabrication of a powerconverter circuit according to embodiments herein.

The foregoing and other objects, features, and advantages of embodimentswill be apparent from the following more particular description ofpreferred embodiments herein, as illustrated in the accompanyingdrawings in which like reference characters refer to the same partsthroughout the different views. The drawings are not necessarily toscale, with emphasis instead being placed upon illustrating theembodiments, principles, concepts, etc.

DETAILED DESCRIPTION

According to example embodiments, a power supply (a.k.a., apparatus)such as a DC-DC power converter includes a voltage converter to producean output voltage to power a load. The power supply further includes areference voltage generator and a controller. During operation, thereference voltage generator generates a floor reference voltage, amagnitude of which varies as a function of the output voltage andsettings of one or more adjustable resistor-capacitor paths (such as azero circuit, gain control circuit, etc.) in the floor reference voltagegenerator. The controller produces control signals to control thevoltage converter as a function of the floor reference voltage and theoutput voltage.

Now, more specifically, FIG. 1 is an example diagram illustrating apower supply including one or more adjustable resistor-capacitor pathsaccording to embodiments herein.

As shown, the power supply 100 (such as an apparatus, hardware, device,system, circuitry, etc.) includes components such as floor referencevoltage generator 110, ramp voltage generator 120, controller 140, andvoltage converter 135. Floor reference voltage generator 110 includesone or more programmable adjustable resistor-capacitor paths 109 tocontrol a behavior (such as phase and gain response) of the floorreference voltage generator 110.

During operation, the reference voltage generator 110 generates a floorreference voltage 115. A magnitude of the floor reference voltage 115varies as a function of the output voltage 123 (or output voltagefeedback signal 192 derived from the output voltage 123) and settings ofthe one or more adjustable resistor-capacitor paths 109 in the floorreference voltage generator 110.

The floor reference voltage generator 110 outputs the floor referencevoltage 115 to the ramp voltage generator 120. As its name suggests, theramp voltage generator 120 produces the offset ramp voltage signal 125,which is a ramp voltage that is offset by the floor reference voltage115. In one embodiment, when magnitude of the floor reference voltagevaries, an offset of the ramp voltage signal with respect to groundvaries.

As further shown, the controller 140 receives the offset ramp voltagesignal 125 produced by the ramp voltage generator 120 and the outputvoltage feedback signal 192. The controller 140 produces the controloutput 165 (output such as one or more control signals) based on acomparison of the output voltage feedback signal 192 and the offset rampvoltage signal 125. As previously discussed, the output voltage feedbacksignal 192 can be any suitable voltage such as the output voltage 123 ora voltage derived from the output voltage 123.

Thus, embodiments herein include a controller 140 that produces controloutput 165 (i.e., control output such as one or more signals) to controlthe voltage converter 135. The controller 140 generates the controlsignals 105 as a function of the floor reference voltage 115 and amagnitude of the output voltage 123.

Note further that the voltage converter 135 receives input voltage 122from the input 111 of the power supply 100. As further shown, thevoltage converter 135 converts the received input voltage 122 from inputvoltage source 121 into the output voltage 123 based on generatedcontrol output 165. Output voltage 123 is outputted from the output 112and powers the load 118.

As previously discussed, and as further discussed herein, the floorreference voltage generator 110 can include one or more adjustableresistor-capacitor paths 109; the programmed settings of the one or moreadjustable resistor-capacitor paths 109 control a behavior of the floorreference voltage generator 110 and generation of the floor referencevoltage 115. In one embodiment, the selected settings of the one or moreadjustable resistor-capacitor paths 109 improve a respective recoverytime of generating the output voltage 123 within a desired voltage rangesubsequent to a transient load condition in which the load 118 suddenlyconsumes more or less current.

FIG. 2 is an example diagram illustrating a power supply andimplementation of multiple adjustable resistor-capacitor paths accordingto embodiments herein.

Note that the power supply 100 as discussed herein can be configured toinclude a controller 140 that controls switching of the power supplybetween different operational modes. For example, the controller 140initiates (via control of switches SW1, SW2, and SW3) switching betweenoperating the power supply 100 in a continuous conduction mode versus adiscontinuous conduction mode (such as diode emulation mode).

During the diode emulation mode, the controller 140 enables (via closingor shorting of switches SW1 and SW3 and opening of switch SW2) thereference generator 143 to control a magnitude of the floor referencevoltage 115 (based on floor reference voltage 115 being generated by thereference generator 143). For example, in this mode, the non-invertinginput of amplifier 220 receives the reference voltage 113 from referencegenerator 143.

Conversely, in the continuous conduction mode, the mode controller 140enables (via opening switches SW1 and SW3 and closing or shorting switchSW2) the floor reference voltage generator circuit 210 and input fromsense amplifier 360 to control the magnitude of the floor referencevoltage 115. In such an instance, a magnitude of the floor referencevoltage 115 varies during non-steady state conditions for driving theload 118. In one embodiment, during steady state conditions, themagnitude of the floor reference voltage 115 is around 550 mVDC,although this can vary depending on the embodiment.

In one nonlimiting example embodiment, the output voltage feedbacksignal 192 and the floor reference voltage 115 (or offset ramp voltagesignal 125) are compared to one another directly via amplifier 260 togenerate the control output 165, optionally also with a soft-startupvoltage signal 195 during a soft-startup of the device. Advantageously,this configuration is implemented when the output voltage feedbacksignal 192 includes a ripple voltage component.

As further discussed below, the control output 165 (such as one or morecontrol signals) is used as a basis to control voltage converter 135(such as a one or more switching phases of power supply 100) forproducing the output voltage 123. In other words, based on controloutput 165 (such as pulse width modulation control information), thevoltage converter 135 produces the output voltage 123 to power therespective load 118.

Further in this example embodiment, note that the sense amplifier 360receives, as input, the output voltage feedback signal 192 and groundreference signal 193 (such as true output voltage 123 at the load 118)to produce an error signal which drives the input (such as resistor R1)of floor reference voltage generator 110.

At steady state (when the magnitude of the output voltage 123 is equalto the setpoint voltage as controlled by the setpoint generator 291),the magnitude of the signal 219 from the amplifier 225 is zero volts (ora steady 600 mVDC offset voltage). Perturbations in the magnitude of theoutput voltage 123 with respect to the desired setpoint causes thesignal 219 to be greater than or less than the 600 mVDC value.

As further shown in the non-limiting example embodiment of FIG. 2, thefloor reference voltage generator 110 includes amplifier 210 and aconfiguration of resistors R1, R2, and R3 in series between the outputof amplifier 225 and the inverting input node of the amplifier 210.Resistors GRES, R5, as well as capacitor GCAP reside in series in afeedback path (adjustable resistor-capacitor path 109-2) between theoutput of amplifier 210 and the inverting input of the amplifier 210.

The floor reference voltage generator 110 is configured to include afirst (outer) gain path (such as combination of resistors R1 and R4) forDC signal gain and a second (inner) gain path (resistors R1 and R2, R3,R5, resistor GRES and capacitor GCAP) for AC signal gain. As previouslydiscussed, the adjustable resistor-capacitor path 109-2 can beprogrammed to provide any suitable AC gain applied to received signal219.

Floor reference voltage generator 210 further includes adjustableresistor-capacitor path 109-1 including a series connectivity ofcapacitor ZCAP and resistor ZRES between the output of the amplifier 225and the inverting input node of the amplifier 210.

In this example embodiment, the first gain path (R1 and R4) provides DC(Direct Current) gain of −R4/R1; the second gain path provides AC(Alternating Current) gain−[GRES+R5]/[R1+R2]. In one embodiment, themagnitude of the DC gain provided by the first gain path issubstantially higher than a magnitude of the AC gain provided by thesecond gain path.

In addition to the use of voltage mode amplifier 210, the settings ofthe passive components R1, R2, R3, GRES, R4, R5 and GCAP are chosen soas to ensure large DC gain and low high frequency gain to improveoverall system accuracy of generating the output voltage 123 at adesired setpoint or within a desired voltage range. Such a configurationalso avoids instability.

Thus, the reference voltage generator 110 includes a floor referencevoltage amplifier 210 operative to produce the floor reference voltage115. The adjustable resistor-capacitor path 109-2 (series combination ofR5, GRES, and GCAP) is disposed in a feedback path of the floorreference voltage amplifier 210. In one embodiment, the adjustableresistor-capacitor path 109-2 controls a gain such as an AC (AlternatingCurrent) gain of the floor reference voltage amplifier 210. Thus,variations in the adjustable resistor-capacitor path 109-2 (such assettings of capacitor or resistors) result in variations to thecorresponding gain provided by the adjustable resistor-capacitor path109-2.

In accordance with further example embodiments, the floor referencevoltage generator 110 includes adjustable resistor-capacitor path 109-1(such as a zero circuit) disposed in a circuit path between an outputnode of a sense amplifier stage 360 (producing signal 219) and an inputof the floor reference voltage amplifier 110. As previously discussed,in one embodiment, the sense amplifier stage 360 compares the outputvoltage feedback signal 192 to a reference setpoint voltage provided bydevice 291. Based on the comparison, the sense amplifier 360 generatessignal 219 (such as an error voltage signal, potentially offset by afixed value such as 600 mVDC).

The sense amplifier 360 inputs the respective generated signal 219 intothe circuit path (adjustable resistor-capacitor path 109-1) to the floorreference voltage amplifier 210. In one embodiment, the adjustableresistor-capacitor path 109-1 provides a zero to the reference voltagegenerator 210 for stability purposes. A programmed setting of theadjustable resistor-capacitor path 109-1 (such as RC value for capacitorZCAP and resistor ZRES) provides and controls a setting of a zeroassociated with the floor reference voltage generator 110.

In one embodiment, the adjustable resistor-capacitor path 109-2 receivesa ripple voltage (such as from the sense amplifier stage 360) andprovides a zero compensation to the floor reference voltage amplifier210 in the floor reference voltage generator 110 for stability.

As previously discussed, during operation in the diode emulation mode,the reference voltage 113 produced by reference generator 143 is coupledto the inverting input of the amplifier 220 via closed switch SW3. Asfurther shown, the non-inverting input of the amplifier 220 is connectedto receive the floor reference voltage 115.

In one embodiment, to operate the floor reference voltage generator 110during the diode emulation mode, the controller 140 sets each of theswitches SW1 and SW3 to an ON state (closed, providing very lowresistive path) and switch SW2 to an OFF state (open, providing a highresistive path). In such an instance, the signal 246 outputted from theamplifier 220 to node 328 overrides the input voltage to resistor R1such that the floor reference voltage generator 610 produces the floorreference voltage 115 to be equal to a fixed value such as 550 mVDC orother suitable value. As shown, the non-inverting input of amplifier 210is set to 600 mVDC or other suitable value.

In accordance with further embodiments, to operate the floor referencevoltage generator 110 in the continuous conduction mode (in which amagnitude of the floor reference voltage 115 varies), the controller 140sets each of the switches SW1 and SW3 to an OFF state (opened, providingvery high resistive path) and switch SW2 to an ON state (closed,providing a low resistive path). In such an instance, the amplifier 220no longer drives a feedback path (specifically node 328) of the floorreference voltage generator 110. Instead, the amplifier 220 is set tooperate in a unity gain mode in which the output of the amplifier 220follows (tracks) the floor reference voltage 115 inputted to thenon-inverting input of amplifier 220. As previously discussed, in theunity gain mode, closed switch SW2 connects the output of the amplifier220 to the inverting input of the amplifier 220. Open switch SW1 ensuresthat the output of the amplifier 220 does not drive node 328 betweenresistor R2 and resistor R3.

Thus, in the continuous conduction mode, the output of the amplifier 220is disconnected from driving the feedback path (such as node 328 orresistor R4) of floor reference voltage generator 110. In such aninstance, the amplifier 210 produces the floor reference voltage 115based upon variations in the magnitude of the output voltage feedbacksignal 192 with respect to the setpoint 288 as sensed by sense amplifier360.

Note further that, when the mode controller 140 switches back tooperating in the diode emulation mode of operation in which thereference generator 143 controls a magnitude of the floor referencevoltage 115, the amplifier 220 produces at least initially drives thenode 328 between resistor R2 and resistor R3 with the previously trackedvoltage value of the amplifier 220 while it was previously set to theunity gain mode. As previously discussed, in the diode emulation mode,the amplifier 220 causes the floor reference voltage generator 110 todrive the floor reference voltage 115 in accordance with the referencesignal 113 outputted from the reference generator 143.

In accordance with further embodiments, regardless of the selected floorreference voltage generator mode, comparator 260 compares the receivedoutput voltage feedback signal 192 to the smaller magnitude of the floorreference voltage 115 and soft start reference 195 to produce outputcontrol 165. As further discussed below, the control output 165 controlsone or more switches in the voltage converter 135 in FIG. 6 to convertthe input voltage into a respective output voltage 123.

FIG. 3 is an example diagram illustrating a specific implementation ofmultiple adjustable resistor-capacitor paths according to embodimentsherein.

In this example embodiment, the capacitor ZCAP is implemented as acapacitor ladder including capacitor Z1, Z2, . . . ZN. The controller140 (or other suitable entity) produces control signal 305 (such as adigital string of data bit information) indicating how to set thecapacitor ZCAP in the adjustable resistor-capacitor path 109-1. Decoder321 decodes the control signal 305 into control signal 306, whichcontrols settings of the switches S2, . . . , SN. Control of switchesS2, S3, . . . SN, determines a magnitude of the capacitor ZCAP based onhow many capacitors Z1, Z2, etc., of the capacitor ladder are connectedin series or parallel. The combination of the capacitor ZCAP andresistor ZRES (such as a fixed or adjustable value) controls settings ofthe respective adjustable resistor-capacitor path 109-1 (zero circuit).

Note that the configuration of the adjustable resistor-capacitor path109-1 in FIG. 3 is shown by way of a non-limiting example embodimentonly. Note that either or both of the components (such as capacitor ZCAPor resistor ZRES) can be programmed to desired resistance or capacitancevalues to provide a desired circuit behavior (response) based onrespective control signals from controller 140.

Thus, in one embodiment, the adjustable resistor-capacitor path 109-1can be configured to include a capacitor ladder (multiple capacitors).The power supply further includes a first RC (resistor-capacitor) pathcontroller 140 (and/or decoder 321) that controls a capacitance of thecapacitor ladder (such as capacitor ZCAP) in the adjustableresistor-capacitor path 109-1 to a desired capacitance setting. Thefirst RC path controller (such as controller 140 and/or decoder 321)selects how many of the one or more capacitors (Z1, Z2, etc.) of thecapacitor ladder are connected in parallel or series depending on arespective control signal 306 inputted to the capacitor ladder. Viachanges in the number of capacitors of the capacitor ladder that areconnected in parallel or series, the first RC path controller controls acapacitance setting and the overall RC setting of the adjustableresistor-capacitor path 109-1 and corresponding circuit behavior(response) associated with the floor reference voltage generator 110.

Further in this non-limiting example embodiment, the resistor GRES isimplemented as a resistor ladder including resistor G1, G2, . . . GM.The controller 140 (or other suitable entity) produces control signal315 (such as a digital string of data bit information) indicating how toset the resistor GRES in the adjustable resistor-capacitor path 109-2.Decoder 322 decodes the control signal 315 into control signal 316,which controls settings of the switches T2, . . . , TM. Control ofswitches T2, . . . , TM determines a magnitude of the resistor GRESbased on how many resistors G1, G2, G3, etc., of the resistor ladder areconnected in series or parallel. The combination of the resistor GRESand capacitor GCAP controls AC gain settings of the respectiveadjustable resistor-capacitor path 109-2 (gain control circuit).

Note that the configuration of the adjustable resistor-capacitor path109-2 in FIG. 3 is shown by way of a non-limiting example embodimentonly. Either or both of the components (such as resistor GRES orcapacitor GCAP) can be programmed to desired resistance or capacitancevalues to provide a desired circuit behavior based on respective controlsignals 315 from controller 140.

Thus, in one embodiment, the adjustable resistor-capacitor path 109-2includes a resistor ladder (such as resistor GRES including multipleresistors G1, G2, G3, etc.). The power supply 100 further includes asecond RC (resistor-capacitor) path controller (such as controller 140and/or decoder 322) that controls a resistance of the resistor ladder inthe adjustable resistor-capacitor path 109-2 to a desired resistorsetting. The second RC path controller selects how many of the one ormore resistors of the resistor ladder are connected in paralleldepending on a respective control signal 316 inputted to the resistorladder. Via changes in the number of resistors of the resistor ladderthat are connected in series or parallel, the second RC path controllercontrols a resistance setting and thus overall RC setting of theadjustable resistor-capacitor path 109-2 and corresponding circuitattributes associated with the floor reference voltage generator 110.

In accordance with further example embodiments, the power supply 100(such as an integrated circuit or other suitable form) includes adigital state machine 202 that automatically tunes a respective settingof each of the one or more adjustable resistor-capacitor paths109 basedon one or more parameters such as:

1) ON time selection/switching frequency of operating the voltage 135.For example, in one embodiment, a user implementing power supply 100selects a preferred switching frequency (E.g. 800 kHz, 1 MHz, 2 MHz . .. ) of operating the voltage converter 135 within a predefined range ofvalues by connecting one pin of the power supply 100 to an externalresistor RCTL. In such an instance, the controller 140 determines asetting (resistance value) of the external resistor RCTL and, based onthe resistance value, the digital state machine 202 then sets up theoptimal resistor-capacitor values for the respective adjustableresistor-capacitor paths 109.

2) An output current 297 supplied by the output voltage 123 to the load118. For example, the controller 140 measures current 297 and maps thedetected output current 297 to an appropriate setting of the respectiveadjustable resistor-capacitor path.

3) IC (Integrated Circuit) temperature. In one embodiment, the powersupply 100 and corresponding one or more components are disposed in anintegrated circuit (such as semiconductor chip or other suitableentity). The controller 140 measures a temperature of a component suchas of the chip, adjustable resistor-capacitor path, etc., and selects anappropriate setting based on the detected temperature. In oneembodiment, there is an optimal setting of resistor-capacitorcombination based on measured temperature.

In accordance with further example embodiments, the digital statemachine 202 generates control signals 305 and 315 to control settings ofthe adjustable resistor-capacitor paths as further discussed below inFIG. 3.

FIG. 4 is an example diagram illustrating a transfer function associatedwith the floor reference voltage generator for different zero settingsof a respective adjustable resistor-capacitor path according toembodiments herein according to embodiments herein.

In this example embodiment, assume that the adjustableresistor-capacitor path 109-2 is set to a first programmed setting.Selection of the setting associated with the adjustableresistor-capacitor path 109-1 (zero circuit) provides a first circuitresponse. For example, for a first programmed setting of the adjustableresistor-capacitor path 109-1 (such as resistor ZRES set to a fixedvalue and capacitor ZCAP set to a first capacitance value), the floorreference voltage generator 110 has a phase response PHR1 and gainresponse GAR1.

As previously discussed, the adjustable resistor-capacitor path 109-1can be adjusted (programmed) to provide a different circuit behavior(such as transfer function, gain response, phase response, etc.). Thatis, changing the capacitance associated with the capacitor ZCAP providesa different phase/gain response for the floor reference voltagegenerator 210. As a more specific example, for a second programmedsetting of the adjustable resistor-capacitor path 109-1 (such asresistor ZRES set to a fixed value and capacitor ZCAP set to a secondcapacitance value greater than the first capacitance value), the floorreference voltage generator 110 has a phase response PHR2 and gainresponse GAR2.

Changing the capacitance associated with the capacitor ZCAP provides yeta different phase/gain response. As a more specific example, for a thirdprogrammed setting of the adjustable resistor-capacitor path 109-1 (suchas resistor ZRES set to a fixed value and capacitor ZCAP set to a thirdcapacitance value greater than the second capacitance value), the floorreference voltage generator 110 has a phase response PHR3 and gainresponse GARS.

In this manner, the adjustable resistor-capacitor path 109-1 can beadjusted to any suitable value and provide a desired response.

FIG. 5 is an example diagram illustrating a transfer function associatedwith implementation of an AC gain adjustment provided via control of acorresponding adjustable resistor-capacitor path according toembodiments herein according to embodiments herein.

Note that the first (or any) programmed setting of the adjustableresistor-capacitor path 109-2 in FIG. 4 can be adjusted to providehigher or lower gain between the input and output of the floor referencevoltage generator 110. For example, as shown in FIG. 5, an increase in aresistance GRES associated with the adjustable resistor-capacitor path109-2 results in an increase in AC gain provided by the floor referencevoltage generator 110.

More specifically, a combination of setting the adjustableresistor-capacitor path 109-2 to the first programmed setting aspreviously discussed and selection of the setting associated with theadjustable resistor-capacitor path 109-1 (zero circuit) as previouslydiscussed provides a first circuit response (phase response PHR1 andgain response GAR1. Increasing a magnitude of the resistance associatedwith the resistor GRES of the adjustable resistor-capacitor path 109-2(via corresponding reprograming) provides an increased gain as indicatedby gain response GAR1′. In other words, if desired, the original gainresponse GAR1 and phase response PHR1 can be tweaked to gain responseGAR1′ and phase response PHR1 based on adjusting the adjustableresistor-capacitor path 109-2.

Thus, a combination of reprogramming settings associated with one orboth of adjustable resistor-capacitor path 109-1 and adjustableresistor-capacitor path 109-2 enables the floor reference voltagegenerator 110 to provide any desired response.

FIG. 6 is an example diagram illustrating implementation of a voltageconverter according to embodiments herein.

In one nonlimiting example embodiment, the voltage converter 135 is aDC-to-DC buck converter operative to produce the output voltage 123 fromthe input voltage 121. However, note that the voltage converter 135 canbe implemented in any suitable manner according to embodiments herein.

As shown, the voltage converter 135 used to generate output voltage 123includes driver circuitry 215-1, driver circuitry 215-2, high sideswitch circuitry 150-1 (such as a control switch or switches), low sideswitch circuitry 160-1 (such as a synchronous switch or switches),controller circuitry 240 and inductor 144-1. Control output 165-1 and165-2 produced by the controller 140 serves as a basis to control highside switch circuitry 150-1 and low side switch circuitry 160-1.

Note that switch circuitry 150-1, 160-1 can be any suitable type ofswitch resource (field effect transistors, bipolar junction transistors,etc.). In one embodiment, each of the high side switch circuitry 150-1and low side switch circuitry 160-1 are power MOSFET (Metal OxideSemiconductor Field Effect Transistor) or other suitable switch devices.

Appropriate switching of the high side switch circuitry 150-1 and thelow side switch circuitry 160-1 results in generation of the outputvoltage 123 as is known in a conventional DC-DC converter such as a buckconverter.

Further in this example embodiment, note that the voltage converter 135receives control output 165 from controller 140 and, on this basis,controls the driver circuitry 215-1 and driver circuitry 215-2 toproduce a PWM1 control signal 310 (PWM1) to control high side switchcircuitry 150-1 and corresponding PWM1* control signal to controllow-side switch circuitry 160-1.

In general, during continuous conduction mode operation of the voltageconverter 135, the low side switch circuitry 160-1 is activated (closedor ON state, low impedance path from drain to source) when the high sideswitch circuitry 150-1 is deactivated (open or OFF state, high impedancepath from drain to source), and vice versa. There is a dead time betweena transition of activating high side switch circuitry 150-1 toactivating low side switch circuitry 160-1. There is a dead time betweena transition of activating low side switch circuitry 160-1 to activatinghigh side switch circuitry 150-1.

On the other hand, during diode emulation mode, the high side switchcircuitry 150-1 is repeatedly pulsed ON and OFF while low side switchcircuitry 160-1 is constantly deactivated (OFF or open circuit).

As previously discussed, the controller 140 (of FIG. 1) can beconfigured to compare the (floor) reference voltage 115 and the outputvoltage feedback signal 192 to determine a timing of activating highside switch circuitry 150-1 of the respective voltage converter 135 toan ON (closed switch) state.

In one embodiment, the floor reference voltage 115 or offset rampreference voltage 125 serves as a threshold value. In such an instance,when the magnitude of the output voltage feedback signal 192 is equalto, crosses, or falls below a magnitude of the offset ramp referencevoltage signal 125, the controller 140 produces the control signals 165to turn ON the high side switch circuitry 150-1 (at which time the lowside switch circuitry 160-1 is turned OFF).

Note further that the power supply 100 and corresponding voltageconverter 135 can be operated in a so-called constant ON-time controlmode in which the PWM (Pulse Width Modulation) setting of the ON-time ofcontrol pulses (such as control signal 165-1) of switch circuitry (suchas high side switch circuitry 150-1) in a phase is constant or fixed;the OFF time of high side switch circuitry 150-1 varies depending upon asubsequent cycle of comparing the output voltage feedback signal 192 andissuance of pulsing the high side switch circuitry 150-1 ON again viasubsequent generate fixed pulse width switch control signals. As therate of decay of the magnitude of the output voltage 123 slows overtime, the frequency of pulsing the high side switch circuitry 150-1 ONagain decreases. Conversely, as the rate of decay of the magnitude ofthe output voltage 123 increase over time, the frequency of pulsing thehigh side switch circuitry 150-1 ON again increases.

Thus, in the constant ON-time control mode in which the ON-time ofactivating the high side switch circuitry 150-1 is a fixed orpredetermined value, the frequency of activating the high side switchvaries to maintain the output voltage 123 to a desired set point.

FIG. 7 is an example timing diagram illustrating switchover fromoperating in a diode emulation mode (discontinuous conduction mode,fixed floor reference voltage mode, diode emulation mode) to operatingin a continuous conduction mode (variable floor reference voltage mode)according to embodiments herein.

As shown in FIG. 7, during diode emulation mode during which the load118 consumes a small amount of current (below a threshold value) priorto time T7, the voltage converter 135 operates in a discontinuousconduction mode (also known as diode emulation mode). In this mode, dueto low or no current consumption by the load 118, the magnitude of theoutput voltage feedback signal 192 can remain above the regulationreference and offset ramp voltage signal 125 for a significant amount oftime without activating the high side switch circuitry 150-1 again. Aspreviously discussed, low side switch circuitry 160-1 is not activatedin the diode emulation mode (such as prior to time t7, which correspondsto 900 microseconds). Optionally, as in the configuration shown, theoffset ramp reference voltage signal 125 is clamped a voltage value suchas 600 millivolts. Accordingly, the offset ramp voltage signal 125 iscyclical; each cycle of the ramp voltage signal 125 has a monotonousportion during which the ramp voltage signal increases or decreases, anda clamped portion in which a magnitude of the ramp voltage signal issubstantially constant (such as 600 millivolts).

One embodiment herein includes, via controller 140, monitoring aparameter such as the amount of current (direct measurement, emulatedcurrent, etc.) delivered to the load via the output voltage 123. Duringa condition in which a monitor circuit (such as controller 140) detectsthat the supplied current such as current through the inductor 144-1 isbelow a threshold value, or when the current is negative flowing fromcapacitor 125 through inductor 144-1 to node 133-1 (FIG.6), thecontroller 140 operates power supply 100 in the diode emulation mode(adjustable floor voltage mode or mode #1) during which switches SW1 andSW3 are closed and switch SW2 is open (see FIG. 2).

In a manner as previously discussed, operation in the adjustable voltagefloor mode (continuous conduction mode after time T8) causes the floorreference voltage 115 to be adjusted to a suitable voltage value suchthat an average magnitude of the output voltage 123 is substantiallyequal to a desired setpoint voltage as controlled by setpoint 288.

When the controller 140 detects that the load 118 consumes substantialcurrent from the generated output voltage 123 again, such as above athreshold value amount of current or a voltage droop of the outputvoltage 123 below a threshold value occurs, the controller 140 switchesto operating in the variable floor mode (mode #2, continuous conductionmode) during which switches S1 and S3 are opened and switch S2 isclosed.

Subsequent to detecting occurrence of one or more conditions such as anincrease in current consumption or droop in the magnitude of the outputvoltage 123 below a threshold value at, around, or for a duration oftime before time T8, which corresponds to 908 microseconds, controller140 switches over to operating the floor reference voltage generator 110in the so-called variable (active) floor mode (mode #2, continuousconduction mode) in which the floor reference voltage 115 variesdepending on the magnitude of the output voltage 191 (or an outputvoltage feedback signal 192).

Thus, after time T8 as shown in timing diagram 700, when the load 118consumes substantial current from the output voltage 123, the voltageconverter 135 produces the output control 165 (or PWM signal 310) tomore frequently activate high side switch circuitry 150-1 for theconstant ON time pulse durations to maintain the output voltage 123within a desired range.

In one embodiment, regulation of the output voltage feedback signal 192at or around 600 mVDC indicates that the output voltage 123 is within adesired regulation. If the magnitude of the output voltage 123 fallsbelow a desired voltage regulation setpoint, the magnitude of the floorreference voltage 115 increases above 550 mVDC; if the magnitude of theoutput voltage 123 raises above the desired voltage regulation setpoint,the magnitude of the floor reference voltage 115 decreases below 550mVDC. At steady state, the floor reference voltage 115 is approximatelysteady at around 540 mVDC.

FIG. 8 is an example block diagram of a computer device for implementingany of the operations as discussed herein according to embodimentsherein.

As shown, computer system 800 (such as implemented by any of one or moreresources such as controller 140, etc.) of the present example includesan interconnect 811 that couples computer readable storage media 812such as a non-transitory type of media (or hardware storage media) inwhich digital information can be stored and retrieved, a processor 813(e.g., computer processor hardware such as one or more processordevices), I/O interface 814, and a communications interface 817.

I/O interface 814 provides connectivity to any suitable circuitry suchas each of phases 110.

Computer readable storage medium 812 can be any hardware storageresource or device such as memory, optical storage, hard drive, floppydisk, etc. In one embodiment, the computer readable storage medium 812stores instructions and/or data used by the control application 140-1 toperform any of the operations as described herein.

Further in this example embodiment, communications interface 817 enablesthe computer system 800 and processor 813 to communicate over a resourcesuch as network 193 to retrieve information from remote sources andcommunicate with other computers.

As shown, computer readable storage media 812 is encoded with controlapplication 140-1 (e.g., software, firmware, etc.) executed by processor813. Control application 140-1 can be configured to include instructionsto implement any of the operations as discussed herein.

During operation of one embodiment, processor 813 accesses computerreadable storage media 812 via the use of interconnect 811 in order tolaunch, run, execute, interpret or otherwise perform the instructions incontrol application 140-1 stored on computer readable storage medium812.

Execution of the control application 140-1 produces processingfunctionality such as control process 140-2 in processor 813. In otherwords, the control process 140-2 associated with processor 813represents one or more aspects of executing control application 140-1within or upon the processor 813 in the computer system 800.

In accordance with different embodiments, note that computer system 800can be a micro-controller device, logic, hardware processor, hybridanalog/digital circuitry, etc., configured to control a power supply andperform any of the operations as described herein.

Functionality supported by the different resources will now be discussedvia flowchart in FIG. 9. Note that the steps in the flowcharts below canbe executed in any suitable order.

FIG. 9 is an example diagram illustrating a method of providingcompensation in a power converter according to embodiments herein.

In processing operation 910, the voltage converter 135 produces anoutput voltage 123 to power a load 118.

In processing operation 920, the floor reference voltage generator 210generates a floor reference voltage 115 that varies as a function of theoutput voltage 123 (and/or a derivative of the output voltage 123 suchas output voltage feedback signal 192) and depending on a setting of anadjustable resistor-capacitor path 109.

In processing operation 930, the controller 140 produces control outputto control the voltage converter 135 as a function of the floorreference voltage 115 and the output voltage 123 (or output voltagefeedback signal 192 derived from the output voltage 123).

FIG. 10 is an example diagram illustrating fabrication of a powerconverter circuit on a circuit board according to embodiments herein.

In this example embodiment, fabricator 1040 receives a substrate 1010(such as a circuit board).

The fabricator 1040 further affixes the power supply 100 (andcorresponding components) to the substrate 1010. Via circuit path 1022(such as one or more traces, etc.), the fabricator 1040 couples thepower supply 100 to the load 118. In one embodiment, the circuit path1022 conveys the output voltage 123 generated from the power supply 100to the load 118. Via the power supply 100 and corresponding components,the power supply 100 converts a received input voltage 121 into arespective output voltage 123 that drives load 118.

Accordingly, embodiments herein include a system comprising: a substrate1010 (such as a circuit board, standalone board, mother board,standalone board destined to be coupled to a mother board, etc.); apower supply 100 including corresponding components as described herein;and a load 118. As previously discussed, the load 118 is powered basedon conveyance of output voltage 123 and corresponding current 131conveyed over circuit path 1022 from the power supply 100 to the load118.

Note that the load 1518 can be any suitable circuit or hardware such asone or more CPUs (Central Processing Units), GPUs (Graphics ProcessingUnit) and ASICs (Application Specific Integrated Circuits such thoseincluding one or more Artificial Intelligence Accelerators), which canbe located on the substrate 1010 or disposed at a remote location.

Note again that techniques herein are well suited for use in circuitapplications such as those that implement power conversion. However, itshould be noted that embodiments herein are not limited to use in suchapplications and that the techniques discussed herein are well suitedfor other applications as well.

Based on the description set forth herein, numerous specific detailshave been set forth to provide a thorough understanding of claimedsubject matter. However, it will be understood by those skilled in theart that claimed subject matter may be practiced without these specificdetails. In other instances, methods, apparatuses, systems, etc., thatwould be known by one of ordinary skill have not been described indetail so as not to obscure claimed subject matter. Some portions of thedetailed description have been presented in terms of algorithms orsymbolic representations of operations on data bits or binary digitalsignals stored within a computing system memory, such as a computermemory. These algorithmic descriptions or representations are examplesof techniques used by those of ordinary skill in the data processingarts to convey the substance of their work to others skilled in the art.An algorithm as described herein, and generally, is considered to be aself-consistent sequence of operations or similar processing leading toa desired result. In this context, operations or processing involvephysical manipulation of physical quantities. Typically, although notnecessarily, such quantities may take the form of electrical or magneticsignals capable of being stored, transferred, combined, compared orotherwise manipulated. It has been convenient at times, principally forreasons of common usage, to refer to such signals as bits, data, values,elements, symbols, characters, terms, numbers, numerals or the like. Itshould be understood, however, that all of these and similar terms areto be associated with appropriate physical quantities and are merelyconvenient labels. Unless specifically stated otherwise, as apparentfrom the following discussion, it is appreciated that throughout thisspecification discussions utilizing terms such as “processing,”“computing,” “calculating,” “determining” or the like refer to actionsor processes of a computing platform, such as a computer or a similarelectronic computing device, that manipulates or transforms datarepresented as physical electronic or magnetic quantities withinmemories, registers, or other information storage devices, transmissiondevices, or display devices of the computing platform.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of the presentapplication as defined by the appended claims. Such variations areintended to be covered by the scope of this present application. Assuch, the foregoing description of embodiments of the presentapplication is not intended to be limiting. Rather, any limitations tothe invention are presented in the following claims.

We claim:
 1. A power supply comprising: a voltage converter to producean output voltage to power a load; a reference voltage generatoroperative to generate a floor reference voltage that varies as afunction of the output voltage and depending on a setting of anadjustable resistor-capacitor path in the floor reference voltagegenerator; and a controller to produce control output to control thevoltage converter as a function of the floor reference voltage and theoutput voltage.
 2. The power supply as in claim 1 further comprising: aramp voltage generator operative to produce a ramp voltage, the rampvoltage being offset by the floor reference voltage; and wherein thecontroller is operative to produce the control output based on acomparison of the output voltage to the offset ramp voltage.
 3. Thepower supply as in claim 1, wherein the reference voltage generatorincludes a floor reference voltage amplifier operative to produce thefloor reference voltage; and wherein the adjustable resistor-capacitorpath is disposed in a feedback path of the floor reference voltageamplifier.
 4. The power supply as in claim 3, wherein the adjustableresistor-capacitor path is operative to control an AC (AlternatingCurrent) gain of the floor reference voltage amplifier.
 5. The powersupply as in claim 1, wherein the reference voltage generator includes afloor reference voltage amplifier operative to produce the floorreference voltage; wherein the adjustable resistor-capacitor path isdisposed in a circuit path between an output of a sense amplifier stageand an input of the floor reference voltage amplifier; and wherein thesense amplifier stage is operative to input an error voltage signal intothe circuit path to the floor reference voltage amplifier.
 6. The powersupply as in claim 1, wherein the adjustable resistor-capacitor pathprovides a setting of a zero associated with the floor reference voltagegenerator.
 7. The power supply as in claim 1, wherein the adjustableresistor-capacitor path controls a phase response associated with theadjustable resistor-capacitor path.
 8. The power supply as in claim 1,wherein the adjustable resistor-capacitor path includes a capacitorladder, the power supply further comprising: a controller operative tocontrol a capacitance of the capacitor ladder to a desired capacitancesetting.
 9. The power supply as in claim 1, wherein the adjustableresistor-capacitor path includes a resistor ladder, the power supplyfurther comprising: a controller operative to control a resistance ofthe resistor ladder to a desired resistance setting.
 10. The powersupply as in claim 1, wherein a magnitude of the floor reference voltagevaries depending on an error signal derived from comparing the outputvoltage to a reference voltage.
 11. The power supply as in claim 1,wherein the adjustable resistor-capacitor path receives a ripple voltageand provides zero compensation to a floor reference voltage amplifier inthe floor reference voltage generator.
 12. The power supply as in claim1, wherein the reference voltage generator includes a floor referencevoltage amplifier operative to produce the floor reference voltage; andwherein the adjustable resistor-capacitor path is a first adjustableresistor-capacitor path disposed in a feedback path of the floorreference voltage amplifier, the first adjustable resistor-capacitorpath being operative to control an AC (Alternating Current) gain of thefloor reference voltage amplifier, the power supply further comprising:a second adjustable resistor-capacitor path providing a setting of azero associated with the floor reference voltage generator.
 13. A methodcomprising: producing an output voltage to power a load; via a referencevoltage generator, generating a floor reference voltage that varies as afunction of the output voltage and depending on a setting of anadjustable resistor-capacitor path; and producing control output tocontrol the voltage converter as a function of the floor referencevoltage and the output voltage.
 14. The method as in claim 13 furthercomprising: producing a ramp voltage, the ramp voltage being offset bythe floor reference voltage; and wherein producing the control outputincludes producing the control output based on a comparison of theoutput voltage to the offset ramp voltage.
 15. The method as in claim 13further comprising: receiving a control signal; and via the controlsignal, controlling the setting of the adjustable resistor-capacitorpath, the adjustable resistor-capacitor path disposed in a feedback pathof the floor reference voltage amplifier.
 16. The method as in claim 13,wherein the setting of the adjustable resistor-capacitor path controlsan AC (Alternating Current) gain of the floor reference voltageamplifier.
 17. The method as in claim 13 further comprising: inputtingan error voltage signal into the adjustable resistor-capacitor path ofthe floor reference voltage generator.
 18. The method as in claim 13,wherein the adjustable resistor-capacitor path provides a setting of azero associated with the floor reference voltage generator.
 19. Themethod as in claim 13, wherein the setting of the adjustableresistor-capacitor path controls a phase response associated with thefloor reference voltage generator.
 20. The method as in claim 13,wherein the adjustable resistor-capacitor path includes a capacitorladder, the method further comprising: selecting the setting of theadjustable resistor-capacitor path via control of the capacitor ladderto a desired capacitance.
 21. The method as in claim 13, wherein theadjustable resistor-capacitor path includes a resistor ladder, themethod further comprising: selecting the setting of the adjustableresistor-capacitor path via control of the resistor ladder to a desiredresistance.
 22. The method as in claim 13, wherein a magnitude of thefloor reference voltage varies depending on an error signal derived fromcomparing the output voltage to a reference voltage.
 23. The method asin claim 13 further comprising: receiving a ripple voltage as input tothe adjustable resistor-capacitor path, the adjustableresistor-capacitor path providing zero compensation to a floor referencevoltage amplifier in the floor reference voltage generator.
 24. Themethod as in claim 13, wherein the adjustable resistor-capacitor path isa first adjustable resistor-capacitor path disposed in a feedback pathof a floor reference voltage amplifier of the floor reference voltagegenerator, the method further comprising: via a setting applied to thefirst adjustable resistor-capacitor path, controlling an AC (AlternatingCurrent) gain of the floor reference voltage amplifier; and via a secondadjustable resistor-capacitor path in the floor reference voltagegenerator, controlling a setting of a zero associated with the floorreference voltage generator.
 25. Computer-readable storage hardwarehaving instructions stored thereon, the instructions, when carried outby computer processor hardware, cause the computer processor hardwareto: produce an output voltage to power a load; generate a floorreference voltage that varies as a function of the output voltage anddepending on a setting of an adjustable resistor-capacitor path; andproduce control output to control the voltage converter as a function ofthe floor reference voltage and the output voltage.
 26. A systemcomprising: a circuit substrate; and the power supply of claim 1, thepower supply fabricated on the circuit substrate.
 27. A methodcomprising: receiving a circuit substrate; and fabricating the powersupply of claim 1 on the circuit substrate.
 28. The method as in claim1, wherein the setting of the adjustable resistor-capacitor path isautomatically tuned by a digital state machine based at least one of: i)a selected switching frequency of operating the voltage converter, ii)an output current of the voltage converter, and iii) a measuredtemperature.